I have a blinking check engine light and would like some assitance if anyone can tell me what might be the cause of it.
I had a steady check engine light and the car was running rough and as the weather started to get cold the car became harder and harder to start in the morning when the engine was cold. The radiator fan also ran all the time. A friend who knows how to check the OB1 codes said it indicated a coolant sensor problem. We replaced that and the car runs fine now. However there is a steady flashing check engine light now and it is not flashing a code. I also had the battery run down and charged it up recently and it seams to operate fine. Could the light be indicative of a batery or a charging system problem?

 

Is it possible your friend left the diagnostic plugs connected together? This is the only reason I know of for a flashing CEL on an OBDI car since it has no misfire detection/flashing CEL on misfire as OBDII does.
As for the battery, it could be the battery itself getting weak and not holding a charge properly, the alterntor not charging sufficiently, or a parasitic drain in the car discharging the battery when it isn't being driven.

 

Thanks for the reply, will check on the plug in the morning and let you know if it is the fix.